Burnt plug on A/C shore power

[RobGunn]

So the last couple seasons I have had a reoccurring plug issue. 30 amp female plug connecting to the male inlet on the boat gets burnt by the end of the season. All three A/C units seems to work OK and I never get any power breaker trip. I have replaced the female plug each year. This year I am replacing both the female and male. I hope to see the issue finally go away.
Just wondering if anyone has an idea why I have keep seeing this. Please feel free to input whatever suggestions you may have.

[km1125]

Usually it's due to either dirty connections at the plug in, or bad/loose wires on the back side of the connector.

Replacing both is a good idea.

[Viper]

If you have the same AC units as me with the 3 knobs, that's a lot of power to be drawing through a 30 amp circuit continuously. There are a lot of variables but the plug is bound to heat up, and once that starts, it's down hill from there. You can get away with 3 modern units on a 30A circuit but you're really taxing it with older ones. My model came with two 50 amp circuits because of that. And it's totally not uncommon for the breaker not to trip even when it finally heats up so much it catches fire!

[KenGrant]

Poor connections cause The connectors to heat up and fail. The Hubbell brand is the best quality. Look for the circle you will listing on anything you buy.

[KenGrant]

(UL). Circle UL that is.

[buster53]

Ok, does the boat stay plugged in all the time or do you plug/unplug every time you go to the boat? If you frequently plug/unplug, make sure nothing on the boat is turned on. If anything is on, when you plug/unplug, it will cause an electrical arc. All these arc’s add up to serious burns on the connections. On my boat, any time I plug/unplug, I make sure the main breakers on the boat are turned off so there is no chance of arcing.

[tomschauer]

A couple things that may help. Ask your marina to install new receptacles on the power post. If needed, offer to supply the receptacles. Ask them to replace the wires from the breakers to the receptacles.
Use some fine sandpaper or emory cloth and clean the male ends of your cords and the male ends on your boat. They should be shinny clean,
If your contact points are at all corroded, the amperage will be transferred via the best contact surface, and not the complete surface, which will create hot spots and other issues.

[bud37]

Resistance from corrosion can create a lot of heat which can travel up the line.....replacing both sides of your connection at the boat end is a good start (assuming the problem only exists at the boat end ) with quality male and female plugs and use the locking ring to hold all firm and tight. You are drawing quite a load thru that line and need it to be as perfect as possible.
FWIW.....The general rule for disconnecting and connecting shore power cords for safety is disconnect from the dock pedestal first and connect to the dock pedestal last.

[RobGunn]

Thanks all for the input. Hopefully by replacing both the female and male will take care of the issue. I will keep a eye on the connection throughout this season and let you all know how it goes.

[Cooler]

Make sure to check condition frequently. That can be a fire accident looking for a place to happen. Also, if you are at a marina with dockhands working through the season, inform the dockmaster and they can also do visual check frequently. That burning event is pretty serious. Good luck. er